The present invention relates to a key and, more particularly, to a door key assembly of arm type capable of adjusting an opening angle of a door to discriminate an outsider or preventing an unauthorized personnel from being invaded to achieve prevention of crimes.
In a conventional art, the applicant of this application has provided an arm type key, in which a key body provided with a dead bolt capable of projecting and retracting is secured to a door. The frame of the door has an upper end portion to which a fixing plate provided with a slide hole (guide hole) is secured. The key is provided with a door opening angle limiting arm which is provided with an engaging hole at the lower end of the arm to be engageable with the dead bolt. A movable pin (guide pin) is also provided for the arm at the upper and thereof. The door opening angle limiting arm is slidably attached to the fixing plate through a return spring in a manner that the movable pin is engaged with the slide hole of the fixing plate.
However, the door key assembly of the prior art described above provides the following defect. Namely, it is required for the guide hole arranged along the moving direction of the guide pin to have a large size in the widthwise direction of the fixing plate, so that it is difficult to attach the key to a door having a thin thickness of the door. In addition, the movement of the door opening angle limiting arm is limited to the size or location of the guide hole, so that the key may be damaged if the key is forcibly moved with the arm taken out.
With another type conventional key such as disclosed in the Japanese Utility model Paid-open Publication No. 60-70166, a door opening angle limiting arm supported to a fixing plate by a movable pin may be slid in an inclined manner in association with the movement of the arm during the door opening operation, and as the sliding resistance increases, the key may be damaged by unnatural force applied to the fixing portion of the arm when the arm is pulled outwardly. In addition, since an arm return spring and a slider are arranged to the rear side of the fixing plate, the thickness of the key itself is made unnecessarily large, resulting in the formation of the deep hole in a door frame to accommodate the same and hence, involving a troublesome working for attaching the key to the door. Moreover, it is desired to avoid the incorporation of a large return spring.
Furthermore, the keys of the prior art described above lack in the outer appearance for the provision of the slide holes.